test-specification: Make possible to add ASCII art

The ASCII art over the topology must be surrounded by .... and
is codeblock in ASCIIdoc. Since this is only used for ASCII arts
to help describe tests, border and background are white.

test/case/ietf_interfaces/Readme.adoc

@@ -35,3 +35,4 @@ include::static_multicast_filters/Readme.adoc[]
 
 include::vlan_qos/Readme.adoc[]
 
+include::verify_all_interface_types/Readme.adoc[]

test/case/ietf_interfaces/verify_all_interface_types/test.py

@@ -1,19 +1,19 @@
 #!/usr/bin/env python3
-#
-# lo     br-0                    br-Q.40           br-D         br-X
-#  |       |                       |                |            |
-#  o       o      eth-Q.10       br-Q           veth0a.20     eth-X.30
-#                         \     /    \              |            |
-#                          eth-Q     veth0b       veth0a        eth-X
-#                                         `---------'
-
-"""
+r"""
 Verify that all interface types can be created
 
 This test verify that all interface types can be created
 and also, tesing setting the configuration in sequal (this
 takes a little longer time than send it once)
+....
 
+ lo     br-0                    br-Q.40            br-D         br-X
+  |       |                       |                  |            |
+  o       o        ethQ.10       br-Q            veth0a.20      ethX.30
+                          \     /    \               |            |
+                           ethQ       veth0b       veth0a        ethX
+                                          `---------'
+....
 """
 
 import infamy

test/spec/theme.yml

@@ -1,7 +1,7 @@
 extends: default
 font:
   catalog:
-    merge: false
+    merge: true
     SourceCodePro:
       normal: SourceCodePro-Regular.ttf
       bold: SourceCodePro-Bold.ttf
@@ -13,6 +13,10 @@ base:
   font_size: 11
   line_height_length: 1.3
 
+code:
+  background-color: #ffffff
+  border-color: #ffffff
+
 heading:
   font_family: SourceCodePro
   font_style: bold